The present invention relates to a method which enables real-time conversion of analog video signals into digital half-tone data and the converters thereof.
In general, the method of displaying pattern in a computer printer or on a display screen is of the type of dot correspondence. That is, the pattern is merely expressed by a combination of black dots, while the signal produced by an image sensor is an analog one. Therefore, prior to storage, the gray scale of each dot should be converted to a digital data through an analog/digital converter. When in use, the digital data of each dot is taken one by one for converting to a dot corresponding data according to a computer program. Then, the dot corresponding data is transferred to the printer or the display screen for displaying the pattern.
For a size A4 picture document having a resolution of 300 dots per inch with each dot represented by 8 bits (which can be divided into 256 orders of brightness and darkness), a total of 8 million bytes will be required to store a whole page of such a picture document. With the currently most popular AT version of person computers (PC/AT), it will require more than one hour to complete the converting operation. Such software operating speed can hardly meet the requirements for office automation.